The long range goals of this project are to clarify how eukaryotic cells reproduce and how they control their reproduction. The approach is to define the roles that individual gene products play in the initiation and execution of the mitotic cell cycle of Saccharomyces cerevisiae through a genetic analysis of mutants that are defective in various aspects of cell division. The pathway of cdc gene functions in the cell cycle will be further mapped by studies using cdc mutants and methylbenzimidazole carbamate. We will seek to identify the genes whose products perform the following roles in cell division and its control: those that are essential for start, the control step in the cell cycle, those that coordinate growth with division, those that mediate division control in response to polypeptide hormones, and those that function in the fusion of nuclei during conjugation.